In order to perform the microtoming operation, the samples (e.g., tissue samples) are clamped in the sample holder, which is caused by a cutting motion drive unit to perform a reciprocating movement relative to the cutting unit, thereby cutting the sample. After such a reciprocating movement; i.e., after a thin section is cut from the sample, the distance between the sample holder and the cutting unit must be reduced by the thickness of the next thin section. This generally horizontal movement is referred to as “feed movement.” The feed movement and the reciprocating movement are in particular orthogonal to each other, the reciprocating movement being vertical and the feed movement being horizontal.
Microtomes are known where the feed movement is produced purely mechanically via free-wheeling lever and/or screw and nut systems. Also known are microtomes where the feed is accomplished electromechanically using stepper motor and screw and nut systems. A microtome including a linear motor for moving the sample holder and the cutting unit relative to each other is known from document DE 10 2008 016165 B5.
The disadvantage of the known microtomes is that the resolution; i.e, the minimum adjustable thickness of the thin sections, is limited by the screw pitch of the screw and nut systems and the minimum step resolution of the stepper motor. To be able to achieve very small steps, and thus very thin sections, it is necessary, in particular, to use very complex designs with expensive screw and nut components. Such designs also require complex, cost-intensive bearing arrangements and are associated with high space requirements and high weight. Moreover, such expensive designs having high-resolution screw and nut components and corresponding motors have the disadvantage that they do not allow rapid movement of the sample holder relative to the cutting unit and, therefore, the feed can be effected only very slowly during sample change in the so-called coarse feed mode of the microtome.
Patent Publications DE 38 20 085 C1, DD 33 313 A1, DE 19 22 739 U, U.S. Pat. No. 5,282,404 A, U.S. Pat. No. 4,377,958 A and DE 10 2009 006 386 B4 describe microtomes in which the object holder is rigidly connected to piezoelectric elements, and the feed movement of the object holder is produced by a change in length of the piezoelectric elements.
Further microtomes are known from documents DE 199 11 163 C1, DE 10 2010 046 498 B3, DE 102 18 927 C1, DE 102 10 408 B4, DE 101 54 843 A1 and DE 36 03 278 C1.